Until the mid 1990s the neurological disorder was believed to be caused almost exclusively by environmental factors, lifestyle and a person's age.
However, now scientists have discovered five more genes that influence its development.
The research, published today (WED) in The Lancet, has been hailed as "an exciting step forward" towards understanding the disease.
It is a progressive disease - meaning it gets worse over time - characterised by uncontrollable shaking and loss of co-ordination of muscles. It affects about 120,000 people in Britain, or one in 500.
The study brings to 11 the total number of genetic regions of the human genome now associated with Parkinson's.
The study - the largest of its kind in the world - mapped and compared the DNA of 12,000 people with Parkinson's and more than 21,000 without it.
The researchers found that the fifth of people with the highest number of genetic "risk variants" were 2.5 times more likely to develop Parkinson's than those with the lowest number.
They concluded: "This study provides evidence that common genetic variation plays an important part in the cause of Parkinson’s disease.
"We have confirmed a strong genetic component to Parkinson’s disease, which, until recently, was thought to be completely caused by environmental factors."
Prof Nick Wood, of the University College London Institute for Neurology, who co-led the study, said: "Discovering five new genes is an exciting step forward and will help us understand more about why and how nerve cells die.
"These findings significantly add to the knowledge base of the increasingly complex picture of the molecules that can cause Parkinson’s."
Dr Kieran Breen, director of research and development at the charity Parkinson’s UK, which helped fund the study, said: " In 2004 Parkinson’s UK funded researchers helped uncover changes in the LRRK2 gene.
"This is one of the most important genes involved in Parkinson’s and studies are looking at whether this may be a target for new drugs.
"In the same way, we hope that the results from this new study will lead to similar advances and help us to move closer towards better treatments, or even a cure for Parkinson’s."